Software configurable distributed antenna system and method for bandwidth compression and transport of signals in noncontiguous frequency blocks
A method for transporting communications signals includes receiving an analog IF signal at a first unit. The analog IF signal includes a first carrier having a first frequency and a first bandwidth and a second carrier having a second frequency different from the first frequency and a second bandwidth. The analog IF signal is converted to a digitally sampled IF signal having the first carrier located in a first Nyquist zone, the second carrier located in a second Nyquist zone, an image of the first carrier located in a third Nyquist zone, and an image of the second carrier located in the third Nyquist zone. The image of the first carrier and the image of the second carrier is transmitted from the first unit to a second unit, where the image of the first carrier and the image of the second carrier is then converted to the analog IF signal.
1. A method for bandwidth compression of a signal, the method comprising:
receiving an analog radio frequency (RF) signal at a first unit, wherein the RF analog signal includes a first carrier having a first frequency and a first bandwidth and a second carrier having a second frequency different from the first frequency and a second bandwidth;
translating the analog RF signal into an analog intermediate frequency (IF) signal;
providing a sampling signal having a sampling frequency;
converting the analog IF signal into a digitally sampled IF signal using the sampling signal, wherein the digitally sampled IF signal includes:
the first carrier in a second Nyquist zone,
the second carrier in a third Nyquist zone,
an image of the first carrier in a first Nyquist zone, and
an image of the second carrier in the first Nyquist zone; and
transmitting the image of the first carrier and the image of the second carrier from the first unit to a second unit.
2. The method of claim 1 , wherein the first unit comprises a digital remote unit (DRU) and the second unit comprises a digital access unit (DAU).
3. The method of claim 1 , wherein the first unit comprises a digital access unit (DAU) and the second unit comprises a digital remote unit (DRU).
4. The method of claim 1 , wherein a frequency of a center of the first Nyquist zone is lower than a frequency of a center of the second Nyquist zone, and wherein the frequency of the center of the second Nyquist zone is lower than a frequency of a center of the third Nyquist zone.
5. The method of claim 1 , further comprising filtering the digitally sampled IF signal.
6. The method of claim 5 , wherein filtering the digitally sampled IF signal comprises filtering out the second Nyquist zone and the third Nyquist zone.
7. The method of claim 1 , wherein transmitting the image of the first carrier and the image of the second carrier from the first unit to the second unit is performed using an Ethernet cable, an optical cable, a microwave link, a coaxial connection, or a wireless link.
8. The method of claim 1 , wherein transmitting the image of the first carrier and the image of the second carrier from the first unit to the second unit is via a parallel connector independent of a serializer/deserializer (SERDES).
9. A system for bandwidth compression of a signal, the system comprising:
a first unit including:
an input port operable to receive an analog radio frequency (RF) signal, wherein the RF analog signal includes a first carrier having a first frequency and a first bandwidth and a second carrier having a second frequency different from the first frequency and a second bandwidth;
an intermediate frequency (IF) processing function operable to translate the analog RF signal into an analog IF signal;
an analog-to-digital converter (ADC) coupled to the IF processing function and operable to convert the analog IF signal into a digitally sampled IF signal wherein:
the first carrier in a second Nyquist zone,
the second carrier in a third Nyquist zone,
an image of the first carrier in a first Nyquist zone, and
an image of the second carrier in the first Nyquist zone; and
a transmission link operable to transmit the image of the first carrier and the image of the second carrier from the first unit to a second unit.
10. The system of claim 9 , wherein the first unit comprises a digital remote unit (DRU) and the second unit comprises a digital access unit (DAU).
11. The system of claim 9 , wherein the first unit comprises a digital access unit (DAU) and the second unit comprises a digital remote unit (DRU).
12. The system of claim 9 , wherein a frequency of a center of the first Nyquist zone is lower than a frequency of a center of the second Nyquist zone, and wherein the frequency of the center of the second Nyquist zone is lower than a frequency of a center of the third Nyquist zone.
13. The system of claim 9 , wherein the first unit further includes a filter coupled to the ADC.
14. The system of claim 13 , wherein the filter is operable to filter out the second Nyquist zone and the third Nyquist zone.
15. The system of claim 9 , wherein the transmission link comprises an Ethernet cable, an optical cable, a microwave link, a coaxial connection, or a wireless link.
16. The system of claim 9 , wherein the first unit further includes a serializer/deserializer (SERDES) coupled to the transmission link.